Locking system for the door of a motor vehicle

ABSTRACT

A motor-vehicle door latch has a latch mechanism, a locking lever movable between a locked position and an unlocked position, a motor drive, and a blocking lever engageable with the locking lever. The locking lever can be decoupled from the blocking lever during fast unlocking so that the locking lever can move into its unlocked position. A spring-loaded force-transmitting lever is coupled to the drive so as to, when displaced thereby in one direction, entrain the locking lever for fast unlocking and so as to, when displaced by the drive in an opposite direction, deflect.

The invention relates to a motor-vehicle door latch with a latchingmechanism formed as a standard pivotal bolt and a latching pawl engagingit, and further with at least one locking lever, preferably a centrallocking lever, and with at least one (electric) motor drive. In additionat least one actuating lever for operation from inside and/or outsidecan be provided.

A motor-vehicle door latch of the above-described type is for exampleknown through German published application 196 27 246. Here a device forfast unlocking of the door latch is also described. Preferably it isconstituted by a solenoid which moves between an extra-security(antitheft-on) position and an unlocked position. In the unlockedposition the latching pawl and the release lever coact such that onactuation of the (outside) actuating lever the pawl is lifted off thepivotal bolt and the respective motor-vehicle door can be opened.

The above-described motor-vehicle door latch has proven effective inpractice, but requires on the one hand the described and speciallymanufactured solenoid and on the other hand a separate and independentcentral-locking drive. This is expensive.

In addition for some time motor-vehicles are known to have so-calledkeyless entry systems that allow entry into the vehicle without the useof the otherwise standard mechanical key. A keyless entry systemfunctions in that the vehicle user carries an identifying device (e.g. acode card) and on approaching the vehicle or when the outside actuator(door handle) is actuated, a transmitter/receiver system exchanges databetween the identifying device and an on-board controller to determine(by comparing codes) if entry is authorized. If the necessaryauthorization is established, the electronic controller transmitssignals to at least one of the door latches of the motor vehicle that isopened by an automatic motorized control element. Such a motor-vehicledoor latch is for example described in German 3,820,248.

In case a door latch in motor vehicles is for example equipped with akeyless entry system, it is particularly necessary when additional useis made of an antitheft mechanism to reduce the time between triggeringof the opening procedures and actual unlocking of the door (preferablyless than 40 ms) such that the system is convenient to operate. This issignificant because the motor-vehicle door latch must after receivingthe door-unlock signal first move from the antitheft-on (extra-security)position and into the unlocked position. Here the central locking drivenormally has an eccentric control pin and at least one fork seat andmust execute two revolutions, so that there is a certain delay (see inthis regard German 196 32 781). The invention proposes a solution tothis problem.

It is a technical object of the invention to improve on a motor-vehicledoor latch of the above-described type such that a relatively delay-freeopening of the motor-vehicle door takes place with no particular extraconstruction cost.

This object is achieved by the invention in a motor-vehicle door latchof the described type wherein for fast unlocking a blocking lever isprovided engaging the locking lever, preferably in its locked and/orantitheft-on position, the locking lever being separated from thelocking lever by means of the (electric) motor drive during fastunlocking so that the locking lever can be moved into its unlockedposition. This can be effected actively or passively. In the first casethe blocking lever after fast unlocking is clear and can be shifted byits own setting member into the necessary unlocked position. Normallythis is done in that the locking lever is moved during the fastunlocking automatically, preferably by a spring, into the unlockedposition.

Also in the scope of the invention is a fast unlocking of the describedmotor-vehicle door latch. Fast unlocking means that the motor-vehicledoor latch in general is moved directly from the antitheft-on,extra-security position or the locked position into the unlockedposition. Thereafter the respective motor-vehicle door can be opened byoperation of the actuating lever (or otherwise). Thus it is conceivablethat the described actuating lever is actuated by an outside door handleso that the latch pawl is lifted off the pivotal bolt and then the doorcan be opened. Basically the fast unlocking can thus be followed by aconventional operation of the actual latch.

A motor-vehicle door latch can be any latch that serves not only forside doors but also for the trunk lid, tailgate, or hood, and even forthe gas cap or the like. In addition it is without doubt within thescope of the invention to provide such a motor-vehicle door latch withadditional devices for electrical opening, antitheft action, and infantsecurity. Electrical opening in this case means that the latch pawl ismoved out of engagement or latching connection with the pivotal bolt bymeans of an (electric) motor force.

In addition motor-vehicle door latches are included where access ismechanical, by means of a door key, door lock, and the respectivedoor-lock nut or even by an electronic key (keyless entry). Of course inthe last case the above-described data exchange takes placeautomatically or is triggered by the user via an actuatable remotecontroller (with its own transmitter).

According to a first alternative of the invention in order to havelocked and antitheft functions or locked and antitheft positions, thelocking lever has two seats. These seats are engageable with a nose onthe blocking lever, as described in German patent application 199 34128.1. In this regard more details are seen in the discussion of thedrawing.

The two seats can be formed as part-circular pockets with differentradial spacings from a rotation axis of the locking lever so thatdifferent positions of the blocking lever are achieved in the locked andantitheft positions. This is normally necessary to ensure that theactuating lever, for example in the locked position of the blockinglever, can lift out of the seat. On the other hand such a system is notusable in the antitheft-on position of the motor-vehicle door latch andis also not desired. In this position the actuating lever moves freely.

According to another alternative embodiment of the invention the lockinglever has a pin working with the blocking lever. This pin engages in apin seat on the blocking lever. In order to establish an antitheft-onposition, in addition there is a (motor-actuated) antitheft lever. Thisantitheft lever can be moved during fast unlocking by means of theblocking lever from the antitheft-on to the antitheft-off position.Simultaneously the pin seat on the blocking lever is lifted off the pinon the locking lever so that this pin and its locking lever are freed.In this manner the already described motor drive serves to operate theblocking lever.

The blocking lever can cooperate with a spring-loaded force-transmittinglever that when operated by the motor drive entrains the locking leverfor fast unlocking. This is most simply done in that theforce-transmitting lever and the blocking lever are mounted on a commonpivot axis and are usually at least partially overlapping and that theforce-transmitting lever has for the necessary coupling an edge engagingthe blocking lever during fast unlocking. In the opposite actuationdirection (of the (electric) motor drive) the force-transmitting leveris deflected by this drive. This is necessary in order that the drivecan according to the invention have an additional function, namely notonly fast unlocking but also central locking.

According to a further alternative embodiment, the blocking lever has anelongated slot at which it is slidably pivoted and along which it isspring-biased. The (electric) motor drive for fast unlocking engagesagainst an actuating edge of the blocking lever. The blocking lever isdeflected via the slidable pivoting on opposite actuation movement ofthe (electric) motor drive (like what was described above) by movementalong the slot.

In order to combine the various functions according to the invention, itis further suggested that the (electric) motor drive be used both forcentral locking (as well as if necessary for fast unlocking) and to thisend has an electric motor with an output wheel or disk and an eccentriccontrol bump. This control bump engages in at least one fork seat on thelocking lever for (central) locking. Preferably two fork seats areprovided, one for the locked position and one for the antitheft-onposition (so long as no additional antitheft lever is employed).

Due to the double-duty of the (electric) motor drive the control bumpalso coacts not only with the force-transmitting lever and/or with theabutment edge of the blocking lever but additionally, as described, withthe one or two fork seats on the locking lever.

As a result an extremely compact construction of the describedmotor-vehicle door latch is obtained that is particularly good for fastunlocking. In fact the output wheel engages with its control bumpnormally already after about a quarter turn with the blocking lever orits force-transmitting lever so that unwanted delay is excluded on fastopening of the motor-vehicle door latch. This is also the case when ithas to be unlocked when in the antitheft-on position and when theunlocking signal is issued by the (central) locking system. In bothcases one gets a nearly delay-free unlocking so that the attachedmotor-vehicle door can be opened immediately.

At the same time the (electric) motor drive takes over the function ofmoving the locking lever, in particular a central locking lever, intoits locking position and/or antitheft-on position. As a result a furtherdrive is not necessary, for a considerable cost advantage. Otherfeatures of the invention have a similar effect of setting the optionalantitheft lever by means of a single (electric) motor drive. In spite ofthis basic possible one can also of course use an additional seconddrive.

The invention always has a particularly simple and clear construction.Here the principal advantages of the invention can be seen.

In the following the invention is described more closely with referenceto a single embodiment. Therein:

FIG. 1 is the latch mechanism belonging to the motor-vehicle door latchaccording to the invention which is shown at a right angle to theelements shown in the following figures;

FIG. 2 is the motor-vehicle door latch according to the invention in afirst embodiment in the locked position;

FIG. 3 is the motor-vehicle door latch according to FIG. 2 in theantitheft-on position;

FIG. 4 is another embodiment of the motor-vehicle door latch accordingto FIGS. 2 and 3;

FIG. 5 is a further variant of the motor-vehicle door latch withantitheft lever in the antitheft-on position; and

FIG. 6 is the motor-vehicle door latch according to FIG. 5 in theantitheft-off position.

In the figures a motor-vehicle door latch is shown which basically has alatching mechanism comprised of a pivotal bolt 1 and a latching pawl 2effective on the pivotal bolt 1. Here the latching pawl 2 is operatedpurely mechanically. Of course the invention also includeselectric-motor driven latching pawls 2 such as basically shown inpublished German patent document 196 50 826 (see FIG. 1). In additionthe basic mechanism has an actuating-lever system with an actuatinglever 3 for inside and/or outside actuation. This actuating lever 3 canbe connected to an unillustrated actuating rod or an actuating bowdencable which leads as is known to an inside and/or outside door handle(see FIGS. 2 through 4).

There is an unillustrated key cylinder which is effective on a key nut4. This key nut 4 serves in turn to pivot a locking lever 5, in thisembodiment a central-locking lever 5. To this end the key nut 4 has anarm 6 that engages a corresponding arm 7 of the locking lever 5 and thustransmits its angular movement to the locking lever 5. These angularmovements are shown in the figures by a double-arrow, V indicating amovement described below in detail into the locked position while Ecorresponds to pivoting into the unlocked position.

The locking lever/central-locking lever 5 cooperates with an insidelocking lever 8 that, like the key cylinder with the key nut 4, servesfor the necessary swinging or pivoting of the locking lever 5 into itslocked, unlocked, and/or antitheft-on positions. There is also anelectric-motor drive 9, 10, 11, and 12. This electric-motor drive 9, 10,11, and 12 is comprised in this embodiment of an electric motor 9, anoutput shaft 10, and an output wheel or wheel 11 meshing with the shaft10. This output wheel 11 has one (or more) eccentric cam bumps 12. Thecam bumps 12 are shown in all figures in the starting position.

The electric motor 9 can rotate the output wheel 11 clockwise andcounterclockwise which as shown in the drawing leads to the locked andunlocked positions (via a blocking lever 13). The antitheft-on positioncan also be set (see German patent application 199 34 128.1). Finallyone can see this blocking lever 13, which serves for fast unlocking ofthe motor-vehicle door latch.

This blocking lever 13 is constructed such that in this embodiment it isengaged with the locking lever 5 either in its locked position (see FIG.2) or in its antitheft-on position (see FIG. 3). To this end the lockinglever 5 has two seat notches 14 and 15 in which a nose 16 of theblocking lever 13 engages. If the nose 16 is in the seat notch 14, thelocking lever 5 is in the locked position (see FIG. 2). If the nose 16engages past into the seat notch 15, the antitheft-on position of thelocking lever 5 is set (see FIG. 3). This is similar to what isdescribed in above-cited German patent application 199 34 128.1 with thesingle difference that in this patent application other latch seats orlatch elements are used (see the references 16 and 17).

The two seat notches 14 and 15 are circularly arcuate with differentradial spacings R₁ and R₂ from a rotation axis 17 of the locking lever5. In this embodiment R₂>R₁. Such a shape insures that in theantitheft-on position of the locking lever 5 the actuating lever 3 isclear of the movement stroke of an edge 18 of the blocking lever 13 (seeFIG. 3).

In the locked position of the locking lever 5, the edge 18 is positionedto pivot the blocking lever 13 out of the seat notch 14 and move it intoan unlocked position as shown by the arrow E at the contact point of theedge 18 in FIG. 2.

The same is true for the variant in FIG. 4 where the edge 18 is providednot at the outside edge but inward in a seat 19 on the actuating lever3. In any case in the locked position of the locking lever 5 unlockingis made possible by the actuating lever 3 while this is not possible inthe antitheft-on position so that the normal and desired functionalityis provided.

In the embodiment of FIGS. 2 and 3 and that of FIGS. 5 and 6 aforce-transmitting lever 21 biased by a spring 20 is provided on theblocking lever 13. When the output wheel 11 and thus the cam bump 12,driven by the motor 9, are rotated clockwise (the unlocking directionE), this cam bump 12 engages after about a quarter turn against theforce-transmitting lever 21. Since the force-transmitting lever 21 andthe blocking lever 13 lie in parallel planes and partially overlap andare pivotal about a common axis 22, this engagement of the cam bump 12causes the force-transmitting lever 23 to entrain the blocking lever 13with an edge 23. The blocking lever 13 thus turns counterclockwise asshown by the arrow in the unlocking direction E. Simultaneously for afast unlocking the engagement nose 16 is pulled out of either of thenotch seats 14 or 15 so that the locking lever 5 is now freed by theblocking lever 13.

Since the locking lever 5 is biased by a hairpin spring 24 in theunlocking direction E, the locking lever 5 will automatically shift intothe unlocked position into engagement with an unillustrated abutment.This means that the motor-vehicle door latch can be opened by actuationof the actuating lever 3 which lifts the latch pawl 2 from the pivotalbolt 1.

When the output wheel 11 is moved counterclockwise in the latchingdirection V the already loaded spring 20 ensures that, starting from theFIG. 2 (and FIG. 5) position, the force-transmitting lever 21 isdeflected against the spring force after about a three-quarter rotationof the control bump 12. Then the control bump 12 engages an edge 25 ofthis force-transmitting lever 21. As soon as the control bump 12 movesoff of this edge 25 on its further movement counterclockwise, theforce-transmitting lever 21 that was pivoted clockwise about the pivotaxis 22 moves back and stops in the position shown in FIGS. 2, 3, 5, and6 because its edge 23 engages the blocking lever 13 and further returnpivoting of the force-transmitting lever 21 is blocked.

The variant according to FIG. 4 operates similarly. Here however thereis no force-transmitting lever 21. Instead the blocking lever 13 has aslot 26 which allows axial shifting of the blocking lever 13. Normallythe blocking lever 13 takes the position shown in the drawing because afurther hairpin spring 27 is braced against it. Rotation of the controlbump 12 through about 90° clockwise (a quarter turn) serves mainly tomove the illustrated motor-vehicle door latch into the unlocked positionE. The control bump 12 engages after moving through the correspondingarc against an abutment edge 28 of the blocking lever 13 so that theblocking lever 13 is turned counterclockwise and its nose 16 leaves thenotch seat 14 or 15 with the corresponding effect on the locking lever5.

When, however, the output wheel 11 is moved clockwise from the startingposition of FIG. 4, after about a three-quarter revolution it reaches afurther edge 29 of the blocking lever 13. Further movement of thecontrol bump 12 pushes the blocking lever 13 downward or deflects theblocking lever 13 along the slot 26.

The locking lever 5 also has two fork seats 30 and 31 see FIGS. 2 and4). These form four control surfaces a, b, c, and for the control pin 12and function generally as described in German patent application 199 34128.1 to which reference is made.

In particular actuation of the control surface a (fork seat 31) servesfor locking of the motor-vehicle door latch with help of the controlbump 12 as shown in FIG. 2. The antitheft-on position of FIG. 2 isassumed by actuation of the control surface c with the control bumpcoacting with the latching lever 4 by engaging in the fork seat 30 andpivoting the latching lever 4 clockwise until the blocking lever 13snaps into the seat 15. The remaining control surfaces b and d serve forunlocking. This is not shown in this embodiment. Here the described fastunlocking is effected via the blocking lever 13 which is operated by thedrive 9, 10, and 11 working with the control bump 12.

Furthermore this electric-motor drive 9, 10, 11, and 12 serves not onlyto set the locked position (see FIG. 2), and the antitheft-on position(see FIG. 3) of the locking lever 5 (via the control surfaces a and c)but also serves for the described fast unlocking via the blocking lever13. It therefore serves two functions.

In order that the system operates as described, the arm 6 of the key nut4 and the coacting arm 7 of the locking lever 5 are in one plane. Thesame is true for the seats 14 and 15. To this end the seats 14 and 15and the arm 7 are formed by a raised part 32 of the locking lever 5.This part 32 and the locking lever 5 pivot jointly about the common axis17. The spring 24 is below the described part 32 and the actual lockinglever 5. The blocking lever 13 is in the same plane with the part 32 sothat its nose 16 can coact in the described manner with the seats 14 and15. The actuating lever 3 extends in the front down (or up) so that itsedge 18 projects up (or down). This ensures that the projecting edge 18can engage the overlying or underlying blocking lever 13 to release thelatch mechanism 1, 2. Finally the control bump 12 of the output wheel 11is generally level with the plane of the locking lever 5 so that thecontrol bump 12 can engage in the fork seats 30 and 31 to have thedescribed functions.

The actuation of the electric-motor drive 9, 10, 11, and 12 takes placein this embodiment for example when the electric motor 9 receives froman unillustrated controller the order “unlock door.” This can take placewith a keyless entry system after the necessary determination of thenearness of the vehicle user. Thereafter the described fast unlocking iseffected by the control bump 12 moving clockwise and pivoting theblocking lever 13 counterclockwise to release the latching lever 4. Ifan outside door handle is operated during the described operations themotor-vehicle door opens immediately.

After unlocking of the door latch (which is monitored via unillustratedtransmitters and sensors) the output wheel 11 is rotatedcounterclockwise into the starting position of FIGS. 2 through 6.

As visible in the illustrated embodiment the locking lever or centrallocking lever 5 is moved by the key nut 4, the electric-motor drive 9,10, and 11 along with the control bump 12 or the inside locking lever 8into the locked and/or antitheft-on positions. The nose 16 of theblocking lever 13 is urged by the spring 27 into the corresponding seat14 or 15.

The unlocking (after a keyless-entry query) is effected by means of thedescribed fast unlocking, that is by about a quarter clockwise rotationof the output wheel 11 with the control bump 12. Independently, thelatching mechanism 1, 2 of the illustrated motor-vehicle door latch canbe opened in the standard manner in that the actuating lever 3 engageswith its edge 18 against the blocking lever 13 in the way known per se.Finally the arm 6 of the key nut 4 can serve for setting the unlockedand antitheft-off positions in that appropriate clockwise rotation ofthe nut 4 and engagement on an edge 33 of the blocking lever 13 freesthe locking lever 5.

In any case fast unlocking requires only a quarter turn (or less) of theoutput wheel 11 so that the motor-vehicle door latch can be openedalmost simultaneously on issuing of the necessary unlocking order forexample via the already gripped outside door handle.

The locking and antitheft functions are handled by appropriate operationof the locking lever 5 by means of the key nut 4, the inside lockinglever 8, or the electric-motor drive 9, 10, 11 together with the controlbump. In the last case the output wheel 11 moves counterclockwise and infact one or two rotations are completed. This sets the desired positionof the locking lever 5 by engagement of the control bump in theappropriate fork seat 30 and/or 31. When the control bump 12 on orbitingcounterclockwise reaches the force-transmitting lever 21 or the blockinglever 13, these are deflected out of the way as described.

The different embodiment of FIGS. 5 and 6 corresponds in its basicoperation to the already described embodiments of FIGS. 1 to 4, so thatreference can be made to that description. Here also the control bump 12is always shown in its starting position. Unlike the system of FIGS. 2to 4 with the two fork seats 30 and 31, here there is only one fork seat31 with the control surfaces and b. The respective locking lever 5 ismoved with the aid of the control surface a into its locked position asshown in FIG. 5.

An antitheft-on position of the locking lever 5 is taken care of by anadditionally provided antitheft lever 34. This antitheft lever 34 isprovided with a (dedicated) motor drive 35, 36. Of course it would bepossible here to use the already described drive 9, 10, 11, and 12. Bymeans of this additional drive 35, 36, 37 the antitheft lever 34 can bemoved between the antitheft-on position (see FIG. 5) and antitheft-offposition (see FIG. 6) by pivoting about an axis 38.

More particularly this is done in that a pin 39 projecting down from theantitheft lever 34 engages in an arcuate slot 40 of an underlying outputdisk 37 that meshes with a spindle 36 driven by an electric motor 35.Operation of the electric motor 35 is effective via the spindle 36 torotate the output disk 37 and entrain the pin 39 of the antitheft lever34 engaged in the arcuate slot 40.

In the antitheft-on position (see FIG. 5) pivoting of the locking lever5 about its axis 17 is not transmitted to the latch mechanism 1, 2because an edge 41 of the antitheft lever 34 decouples it. In otherwords a pin 43 of a connecting lever 42 working with the locking lever 5is held out of engagement with the cited edge 41. The locking lever 5can thus be moved in the unlocking direction E without the pin 43 of theconnecting lever 42 following. In the antitheft off position (FIG. 6) onthe other hand the pin 43 of the connecting lever 42 is free so thatpivoting of the locking lever 5 about its axis 17 effects the desiredunlocking of the latch mechanism 1, 2.

During fast unlocking the antitheft lever 34 is moved by the blockinglever 13 from its antitheft-on position to the antitheft-off position.This is done in this embodiment in that the blocking lever 13 with itsedge 44 moves the antitheft lever 34 about its axis 83. Simultaneouslythe pin 39 moves counterclockwise in the arcuate slot 40 of the outputdisk 37.

Actuation of the blocking lever 13 is as described by means of theoutput wheel 11 working with the control pin 12 which after about aquarter turn, starting from the FIG. 5 illustrated position, engages theforce-transmitting lever 21. For reasons of clarity the remaining partsof the already fully described motor drive 9, 10, 11, and 12, that isthe electric motor 9 and the output shaft 10, are all that is shown inFIGS. 5 and 6.

Unrelated to the antitheft function, the locking lever 5 has a pin 45engageable with the blocking lever 13, that is engageable in a pin seat46 on the blocking lever 13. This engagement takes place automaticallyonly in the case when the locking lever 5 is moved by the electric-motordrive 9, 10, 1, 12 into the locked position shown in FIGS. 5 and 6. Inthis case also only about a quarter turn of the output wheel 11 isneeded in order to separate the blocking lever 13 by means of thecontrol bump 12 engaging the force-transmitting lever 21 from thelocking lever 5. This engagement of the control bump 12 on theforce-transmitting lever 21 lifts the pin seat 46 from the pin 45 sothat the locking lever 5 is moved by spring force into its unlockedposition E (see arrow E in FIG. 6).

Simultaneously and independently the antitheft lever 34 in theantitheft-on position is entrained by the blocking lever 13 via its edge44.

What is claimed is:
 1. A motor-vehicle door latch comprising a latchmechanism; a locking lever movable between a locked position and anunlocked position; a motor drive; a blocking lever engageable with thelocking lever; and means connected to the drive for decoupling thelocking lever from the blocking lever during fast unlocking so that thelocking lever can move into its unlocked position; and a spring-loadedforce-transmitting lever coupled to the drive so as to, when displacedthereby in one direction, entrain the locking lever for fast unlockingand so as to, when displaced by the drive in an opposite direction,deflect.
 2. The motor-vehicle door latch according to claim 1 whereinthe locking lever is moved during the fast unlocking automatically intothe unlocked position.
 3. The motor-vehicle door latch according toclaim 1 wherein in order to have locked and antitheft-on positions, thelocking lever has two seats which are engageable with a nose on theblocking lever.
 4. The motor-vehicle door latch according to claim 3wherein the two seats are part-circular pockets with different radialspacings from a rotation axis of the locking lever so that differentpositions of the blocking lever are achieved in the locked andantitheft-on positions.
 5. The motor-vehicle door latch according toclaim 1 wherein the locking lever has a pin working with the blockinglever.
 6. The motor-vehicle door latch according to claim 5 wherein thepin engages in a pin seat on the blocking lever.
 7. The motor-vehicledoor latch according to claim 1 wherein in addition a preferablymotor-actuated antitheft lever is provided that is moved during fastunlocking by means of the blocking lever from the antitheft-on to theantitheft-off position.
 8. The motor-vehicle door latch according toclaim 1 wherein the blocking lever has an elongated slot at which it isslidably pivoted and along which it is spring-biased, the motor drivefor fast unlocking engaging against an actuating edge of the blockinglever, the blocking lever deflecting via the slidable pivoting onopposite actuation movement of the motor drive.
 9. The motor-vehicledoor latch according to claim 1 wherein the motor drive is used both forcentral locking as well as for fast unlocking and to this end has anelectric motor with an output wheel and an eccentric control bump, thecontrol bump engaging in at least one fork seat on the locking lever forlocking and also coacting with the force-transmitting lever and/or theabutment edge of the blocking lever.